Flat multifilament-yarn textile

ABSTRACT

A flat multifilament yarn woven fabric having a low air permeability and excellent vision through-preventing property and water- or perspiration-absorbing property includes, as warp and/or weft yarns, multifilament yarns formed from a plurality of artificial individual filaments having a flat cross-sectional profile in which, on both the sides of a longitudinal center line of the profile, 3 or more projections projecting outward from the longitudinal center line and 2 or more constrictions formed between the projections, per side of the profile are formed approximately in symmetry with respect to the longitudinal center line, and a degree of flatness of the profile represented by a ratio (B/C1) of a largest length B of the profile in the direction of the longitudinal center line to a largest width C1 of the profile in the direction of right angles to the longitudinal center line is 2 to 6, the woven fabric having a cover factor of 800 to 3500.

TECHNICAL FIELD

The present invention relates to a flat multifilament yarn woven fabric.More particularly, the present invention relates to a woven fabriccomprising multifilament yarns constituted from a plurality ofartificial individual filaments having a flat cross-sectional profilewith two or more constrictions per side section, and exhibiting a softhand, a practically high water absorption, abrasion resistance andvision through-prevention.

BACKGROUND ART

Currently, various types of poorly air-permeable woven fabrics areprovided for sport cloths and uniform cloths. As the lowair-permeability woven fabrics, high density woven fabrics formed fromsynthetic fibers, for example, polyester or polyamide fibers, and coatedwoven fabric in which a resin coating layer is formed on a woven fabric,and calendered woven fabrics, are known.

However, the high density woven fabrics, surface-coated and calenderedwoven fabrics usually have a low softness (a hard hand), and thesurfaces of the fabrics exhibit a low resistance to abrasion (abrasionresistance, and thus these types of woven fabrics must be improved.

Synthetic fibers, for example, polyester and polyamide fibers haveexcellent physical and chemical properties and thus are practically usedin various uses such as clothing and industrial uses. Particularly, thepolyester fibers exhibit excellent mechanical strength, dimensionalstability and an easy-care property, and thus various types of wovenfabric formed from synthetic fibers, for example, polyester fibers, areused widely.

However, the woven fabrics formed from synthetic fibers such aspolyester fibers have, in addition to the above-mentioned advantageousproperties, a high transparency. Thus, when the high transparencysynthetic fibers are formed into a fabric and the fabric is used as anupper garment a problem such that a garment worn under the uppergarment, namely an undergarment, can be seen occurs.

As a means for solving the above-mentioned problem, it is known thatinorganic fine particles, for example, titanium dioxide particles aredistributed into the synthetic fibers. This means can cause theresultant synthetic fibers to exhibit an increased opacity and thus anenhanced see through-preventing property. However, the woven fabricformed from the opaque synthetic fibers still must have an increasedweave density to prevent the transmission of light through gaps formedbetween the yarns from which the woven fabric is formed. This increasein the weave density causes a problem that the resultant woven fabricexhibits a decreased softness.

In the case of woven fabric for interior material, for example,curtains, both the vision through-preventing property (namely a propertyof preventing vision through of an articles and movement of people inthe room, and light transmission must be high. However, usually, thoseproperties are incompatible with each other and thus are extremelydifficult to realize together.

For this reasons, usually, a thin lace curtain is arranged on the windowside and a thick drape curtain is arranged on the room side, and innighttime the drape curtain is closed, and in daytime the lace curtainis closed to satisfy both the requirements of vision through-preventionand of lighting. However, generally speaking, the thick drape curtainhas an excellent vision through-prevention and a poor light-transmittingproperty, and the thin lace curtain has an insufficient visionthrough-preventing property not only in nighttime but also in daytime.Accordingly, it is necessary to solve this problem. To solve theproblem, for example, a light-blocking curtain formed from a combinedweave comprising polyester fiber yarns comprising a delustering agent,for example, titanium dioxide and black colored polyester fiber yarnscontaining a black-coloring pigment and capable of reflecting andabsorbing the light, is disclosed in, for example, Japanese Patent No.3167586; a mirror curtain formed from a woven or knitted fabric on bothor one surface of which fabric sheen gloss yarns are arranged, andhaving a high prevention property of vision through from outside toinside of a room through the curtain, due to scattered light generatedwhen light is irradiated to the sheen gloss surface of the fabric, andsatisfactory ligh-transmitting property and air-permeability, isdisclosed in, for example, Japanese Unexamined Patent Publication No.2000-237,036; and a light-blocking fabric in which a black-coloredlight-shielding layer is formed on a surface of a fabric is disclosedin, for example, Japanese Unexamined Patent Publication No. 62-133,787.

The above-mentioned light-blocking fabric having a black-coloredlight-blocking layer formed on a fabric surface and light-blockingcurtain have a problem that as the light-transmitting property is poor,the inside of the curtained room is dark and an oppressive atmosphere iscreated in the curtained room. Also, the light-transmitting property ofthe mirror curtain is high. However, the mirror curtain has a problemthat the vision through-preventing property of the mirror curtain,particularly in might time, is insufficient, and the sheeting glossyarns cause a garish gloss, on the mirror curtain, to be created.

As mentioned above, a woven fabric having both a sufficientlight-transmitting property and an excellent vision through-preventingproperty and usable in practice, has not yet been provided.

Further, the woven fabric made from synthetic fibers is disadvantageousin that the water-absorbing properties, especiallyperspiration-absorbing property of the synthetic fiber woven fabric ispoorer than that of the woven fabric made from natural fibers, forexample, cotton fibers.

As a means for enhancing the water-absorbing property andperspiration-absorbing property of the synthetic fiber woven fabric, awater absorption-enhancing method in which a hydrophilicizing agent isapplied to the woven fabric is known. Also, in the use of, for example,lining clothes, sport clothes and uniform clothes, further enhancedwater and perspiration-absorbing properties are required.

Under the above-mentioned circumstances, there is a strong demand of anartificial fiber woven fabric, particularly a synthetic fiber wovenfabric, having a soft hand, a high vision through-preventing propertyand an excellent water and perspiration absorbing property.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a flat multifilamentyarn woven fabric exhibiting a hand with a high softness, a high waterand perspiration-absorbing property, abrasion resistance, appropriateair permeability, light transmission and a high see through-preventingproperty.

Another object of the present invention is to provide a flatmultifilament yarn woven fabric useful for constituting textilematerials having an appropriate air permeability, textile materialshaving a high vision through-preventing property, textile materialshaving a high water and perspiration-absorbing property and/or textilematerials having a high abrasion resistance.

The above-mentioned objects can be attained by the flat multifilamentyarn woven fabric of the present invention.

The flat multifilament yarn woven fabric of the present inventioncomprises a plurality of multifilament yarns comprising a plurality ofartificial individual filaments comprising, as a principal component, anartificial fiber-forming polymer and having a flat cross-sectionalprofile,

-   -   wherein in both the side sections of a longitudinal center line        of the flat cross sectional profile of each artificial        individual filament, at least three projections per side section        are projecting outward from the longitudinal center line and at        least two constrictions per side section formed between the        projections are formed approximately in symmetry with respect to        the longitudinal center line, and a degree of flatness of the        cross-sectional profile represented by a ratio (B/C1) of a        largest length (B) of the cross-sectional profile in the        direction of the longitudinal center line to a largest width        (C1) of the cross-sectional profile in the direction at right        angles to the longitudinal center line is 2 to 6, and the woven        fabric has a cover factor of 800 to 3500.

In the flat multifilament yarn woven fabric of the present invention,the artificial fiber-forming polymer is preferably selected frompolyesters, polyamides, polyvinylidene chloride, polypropylene,regenerated cellulose and cellulose acetates.

In the flat multifilament yarn woven fabric of the present invention, inthe cross-sectional profile of the artificial individual filaments, aratio (C1/C2) of the largest width (C1) to a smallest width (C2) ispreferably in the range of from 1.05 to 4.00.

In the flat multifilament yarn woven fabric of the present invention,the total thickness of the multifilament yarns is preferably in therange of from 30 to 170 dtex and the thickness of the individualfilaments is preferably in the range of from 0.5 to 5 dtex.

The flat multifilament yarn woven fabric of the present inventionpreferably has a weave structure selected from plain weave, twill weaveand satin weave structures.

In the flat multifilament yarn woven fabric of the present invention,the multifilament yarns comprising the artificial individual filamentshaving the flat cross-sectional profile is preferably contained in anamount of 10 to 100% by mass based on the mass of the woven fabric.

In an embodiment (1) of the flat multifilament yarn woven fabric of thepresent invention, the cover factor of the woven fabric is in the rangeof from 1500 to 3500.

In the embodiment (1) of the flat multifilament yarn woven fabric of thepresent invention, the multifilament yarn preferably has a number oftwists of 0 to 2500 turns/m.

In the embodiment (1) of the present invention, the flat multifilamentyarn woven fabric preferably has an air permeability of 5 ml/cm²·sec orless, determined in accordance with JIS L 1096-₁₉₉₈, 6.27.1, Method A(using a Frazir type tester).

In the embodiment (1) of the flat multifilament yarn woven fabric of thepresent invention, the air-permeability is preferably in the range offrom 0.1 to 4.0 ml/cm²·sec.

In the embodiment (1) of the present invention, the flat multifilamentyarn woven fabric preferably has a water absorption velocity of 40 mm ormore, determined in accordance with JIS L 1096-₁₉₉₈, 6.26.1, (2) MethodB (Byreck method).

In the embodiment (1) of the present invention, the flat multifilamentyarn woven fabric preferably has an abrasion resistance of 50 abrasions,determined in accordance with JIS L 1096-₁₉₉₈, 6.171., (1) Method A-1(flat surface method).

A low air permeability textile material of the present inventioncomprises a flat multifilament yarn woven fabric of the embodiment (1)of the present invention.

In an embodiment (2) of the flat multifilament yarn woven fabric of thepresent invention, the artificial individual filaments of themultifilament yarn contains 0.2% by mass of a delustering agent, and thecover factor of the woven fabric is in the range of from 1300 to 3000.

In the embodiment (2) of the flat multifilament yarn woven fabric of thepresent invention, the multifilament yarn preferably has a number oftwists of 0 to 1500 turns/m.

In the embodiment (2) of the present invention, the flat multifilamentyarn woven fabric preferably has a degree of vision through-preventionof the woven fabric represented, in a L*a*b* color system, by adifference ΔL(=L*_(w)−L*_(b)) between an L* value of the woven fabricplaced on a white plate, represented by L*_(w), and an L* value of thewoven fabric placed on a black plate, represented by L*_(b), is 15 orless.

In the embodiment (2) of the present invention, the flat multifilamentyarn woven fabric preferably has a water absorption velocity of 40 mm ormore, determined in accordance with JIS L 1096-₁₉₉₈, 6.26.1, (2) MethodB (Byreck method).

A vision through-preventing, perspiration-absorbent textile material ofthe present invention comprises a flat multifilament yarn woven fabricof the embodiment (2) of the present invention.

In an embodiment (3) of the flat multifilament yarn woven fabric of thepresent invention, the artificial individual filaments of themultifilament yarn contains 0 to 0.2% by mass and the cover factor ofthe woven fabric is in the range of from 800 to 2000.

In the embodiment (3) of the flat multifilament yarn woven fabric of thepresent invention, the multifilament yarn preferably has a number oftwists of 0 to 1000 turns/m.

In the embodiment (3) of the present invention, the flat multifilamentyarn woven fabric preferably has a degree of light transmittance of 10to 70%, determined in accordance with JIS L 1055-₁₉₈₇, 6.1. Method A, ata degree of illumination of 100000 lx.

A vision through-preventive textile material of the present inventioncomprises a flat multifilament yarn woven fabric of the embodiment (3)of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory cross-sectional profile of an example of flatmultifilaments usable for the flat multifilament yarn woven fabric ofthe present invention,

FIG. 2 is an explanatory cross-sectional profile of another example offlat multifilaments usable for the flat multifilament yarn woven fabricof the present invention, and

FIG. 3 is an explanatory cross-sectional profile of still anotherexample of flat multifilaments usable for the flat multifilament yarnwoven fabric of the present invention.

BEST MODE OF CARRYING OUT THE INVENTION

The inventors of the present invention have found that, in a wovenfabric comprising, as warp and/or weft yarns, multifilament yarns eachcomprising a plurality of individual filaments comprising an artificialfiber-forming polymeric material and having a flat cross-sectionalprofile, in the case where the cross-sectional profile of each of theindividual filaments has projections projecting outward from alongitudinal center line of the flat profile in the number of 3 or more,preferably 4 or more, still more preferably 4 to 6, per one side sectionof the flat profile with respect to the longitudinal center line of theflat profile, and constrictions formed between the projections, in thenumber of 2 or more, preferably 3 or more, still more preferably 3 to 5,per one side section of the flat profile with respect to thelongitudinal center line of the flat profile, the projections andconstrictions being respectively formed approximately in symmetry withrespect to the longitudinal center line of the flat profile, and aflatness of the cross-sectional profile of the individual filamentrepresented by a ratio (B/C1) of the largest length, in the longitudinaldirection, of the flat profile to a largest width (C1); in the crossdirection at right angles to the longitudinal direction, of the flatprofile is controlled within the range of from 2 to 6, (1) the flatindividual filaments in the flat multifilament yarns of the resultantwoven fabric are closely contacted at flat peripheries thereof with eachother, and at warp-weft yarn-intersecting portions of the woven fabric,the closely contacting flat individual filaments are easily slip-spreadby the compressing pressure of the intersecting warp and weft yarns toeach other, to form, in the woven fabric, broad, dense intersectingportions in which the gaps between the flat individual filaments becomedecreased, and (2) the flat peripheries of the flat individual filamentsclosely contacting each other have a plurality of projections and aplurality of constrictions and thus are roughened, and therefore, thefrictional resistance between the flat individual filaments becomedecreased so that the warp-weft yarn-intersecting portions of theresultant flat multifilament yarn woven fabric exhibit a high softness(flexibility) and a low air permeability.

Further, the inventors of the present invention have found that theplurality constrictions formed on the peripheries of the flat individualfilament causes a capillarity to liquids to be generated and thus thewoven fabric of the present invention to exhibit excellent water andperspiration-absorption property.

Furthermore, the inventors of the present invention have found that theplurality of productions and constrictions formed in the peripheries ofthe flat individual filaments cause the frictional resistance of theperipheries of the flat individual filaments and thus the resultantwoven fabric of the present invention to exhibit an excellent abrasionresistance. Still furthermore, the inventor of the present inventionhave found that the plurality of projections and constrictions formed inthe peripheries of the flat individual filaments in the woven fabric ofthe present invention cause the peripheries to be roughened surfaceswhich scatter light transmitting through the surface by irregularreflections and reflections of the light and thus contribute todecreasing the vision through property of the woven fabric and topreventing seeing an article through the woven fabric, withoutsignificantly decrease the quantity of light transmitted through thewoven fabric (amount of light lighted through the woven fabric).

Moreover, the inventors of the present invention have found that byappropriately establishing the cover factor of the flat multifilamentyarn woven fabric of the present invention in the range of from 800 to3500, the air permeability, water and perspiration-absorbing property,abrasion resistance and vision through-preventing property of the flatmultifilament yarn woven fabric of the present invention can beappropriately controlled and, thereby, various types of textilematerials having the above-mentioned properties can be provided.

The present invention is one completed on the basis of theabove-mentioned findings.

The flat multifilament yarn woven fabric of the present inventioncomprises, as warp and/or weft yarns, a plurality of multifilament yarnseach comprising a plurality of artificial individual filamentscomprising, as a principal component, a fiber-forming artificial polymerand having a flat cross-sectional profile.

In the above-mentioned flat multi-filament yarn woven fabric, forexample, referring to FIG. 1, the profile of a cross-section 1 of anindividual filament is in a flat form in which the width in thedirection at right angles to the longitudinal center line of the profileis relatively small in comparison with the longitudinal length of theprofile.

In the cross sectional profile 1 shown in FIG. 1, in both side sectionsof the profile with respect to the longitudinal center line 2, 3 or moreprojections 3 (4 projections in FIG. 1) projecting outward from thelongitudinal center line and two or more constrictions 4 (3constrictions in FIG. 1) formed between the projections are respectivelyformed per one side section of the profile, approximately in symmetrywith respect to the longitudinal center line 2. In the cross-sectionalprofile of FIG. 1, a flatness of the cross-sectional profile representedby a ratio (B/C1) of a largest length (B) of the profile in thedirection of the longitudinal center line to a largest width (C1) of theprofile in a direction at right angles to the longitudinal center linedirection is in the range of from 2 to 6.

In the cross-sectional profile of each flat individual filament, the 3or more projections and 2 or more constrictions formed in one sidesection of the flat profile are approximately in symmetry, in shape andlocation with respect to the longitudinal center line of the flatprofile, with the 3 or more projections and 2 or more constrictionsformed in the opposite side section of the flat profile, to theabove-mentioned one side section.

In the above-mentioned cross-sectional profile of the flat individualfilaments of the multifilament yarn, the number of the projections is 3or more, preferably 4 or more, still more preferably 4 to 6 per one sideof the flat profile. Also, the number of constrictions is 2 or more,preferably 3 or more, still more preferably 3 to 5, per one side of theflat profile. Also, the flatness of the cross-sectional profile is 2 to6, preferably 3 to 5.

If the number of the projections is 2 or less, and the number of theconstrictions is 1 or less, the peripheries of the resultant individualfilaments exhibit an increased frictional resistance, and thus theslip-spreading of the individual filaments in the warp-weft intersectingportions of the woven fabric in which portions a compressive presence ofthe warp and weft yarns is applied to each other, becomes insufficient,the air permeability of the resultant woven fabric becomes to bedifficult to control, and the abrasion resistance of the resultant wovenfabric becomes insufficient, and the decrease in the number of theconstrictions causes the water and perspiration-absorbing property ofthe resultant woven fabric to be insufficient, and the light-scatteringeffect on the individual filament peripheries to be insufficient andthus the resultant wove fabric exhibits an unsatisfactory visionthrough-preventing property.

In the flat multifilament yarn woven fabric of the present invention,the cross-sectional flatness (B/C1) of the individual filaments of theflat multifilament yarn is 2 to 6, preferably 3 to 5. If thecross-sectional flatness is less than 2, the bending resistance(rigidity) of the individual filaments is too high, the resultant wovenfabric exhibits an insufficient softness, and thus the target soft handof the woven fabric cannot be obtained.

Also, when the cross-sectional flatness is less than 2, in the warp-weftintersecting portions of the woven fabric, the slip-spreading of theindividual filaments in the multifilament yarn due to the compressivepressure of the warp and weft yarns to each other becomes insufficient,the gaps between the warp and weft yarns cannot be sufficiently small,the size of the spaces between the filaments cannot be sufficientlysmall, and thus the air permeability of the resultant woven fabricbecomes difficult to control to a desired level.

Also, individual filaments having a cross-sectional flatness (B/C1) ofmore than 6 are difficult to produce.

In the cross-sectional profile of the flat individual filaments of theflat multifilament yarn usable for the woven fabric of the presentinvention, the ratio (C1/C2) of the largest width (C1) to the smallestwidth (C2) in the direction at right angles to the longitudinal centerline of the flat profile is preferably in the range of from 1.05 to4.00, more preferably 1.10 to 2.50. The ratio (C1/C2) as mentioned aboveis a parameter relating to a depth of the constrictions of the flatindividual filaments. If the ratio (C1/C2) is less than 1.05, namely,the depth of the constriction is too small, the peripheral surfaces ofthe resultant flat individual filaments may exhibit too high africtional resistance and the resultant woven fabric may exhibit toohigh an air permeability and insufficient abrasion resistance, visionthrough-preventing property, and water and perspiration-absorbingproperties. Also, if the ratio (C1/C2) is more than 4.0, the depth ofthe constrictions of the flat individual filaments is too large, theeffects of the constrictions is saturated, and the resultant wovenfabric may be disadvantageous in that the filament-forming proceduresmay be unstable, the resultant individual filaments may be slit alongthe constrictions, and the uniformity in the cross-sectional profile ofthe individual filaments may be degraded.

In each of FIGS. 2 and 3, another embodiment of the cross-sectionalprofile of the flat individual filaments usable for the flatmultifilament yarn woven fabric of the present invention is shown.

The cross-sections of filament 1 shown in FIG. 2 has a profile havingsimilar projections and constrictions formed in both side sections withrespect to the longitudinal center line 2, to those is FIG. 1, exceptthat the profile of the projections in FIG. 2 is in the form of an arcof an ellipse extending along the major axis of the ellipse and thus theform of the ellipse arc is more gentle than that of the circle arc formof the projections of FIG. 1, and thus the depth of the constrictions inFIG. 2 is smaller than that in FIG. 2.

The cross-sectional profile of a filament 1 shown in FIG. 3 hasprojections and constrictions formed in both side sections of the flatprofile with respect to the longitudinal center line and in the numbersof 4 and 3 per one side section of the flat profile, respectively. InFIG. 3, a projection 3 a is smaller in width and height than the other 3projections 3, and thus the depth of the constrictions 4 a formed inboth sides of the projection 3 a namely from the top of the projection 3a to the bottoms of constrictions 4 a is smaller than that of the otherconstrictions 4.

The cover factor of the flat multifilament yarn woven fabric is in therange of from 800 to 3500, as mentioned above, can be appropriatelyestablished in response to the properties and performances necessary tothe woven fabric.

The cover factor (CF) of a woven fabric is defined by the followingequation.CF=(DWp/1.1)^(1/2) ×NWp+(DWf/1.1)^(1/2) ×Mwf

In the above-mentioned equation,

-   -   DWp represents a total thickness (dtex) of the warp yarns,    -   MWp represents a weave density (yarns/2.54 cm) of the warp        yarns,    -   DWf represents a total thickness (dtex) of the weft yarns,    -   MWp represents a weave density (yarns/2.54 cm) of the weft        yarns.

In the flat multifilament yarn woven fabric of the present invention, ifthe cover factor (CF) of the fabric is less than 800, the gaps betweenthe warp and weft yarns is large and the air permeability of the wovenfabric is difficult to control to a desired value and also a wovenfabric having a vision through-preventing property at a desired highlevel is difficult to produce.

Also, if the cover factor (CF) is more than 3500, the resultant wovenfabric exhibits an insufficient softness and an unsatisfactory lighttransmission (lighting property).

The fiber-forming artificial polymer usable for forming the flatmultifilament yarns for the flat multifilament yarn woven fabric of thepresent invention may be selected from fiber-forming synthetic polymers,for example, polyester, polyamide polyvinylidene chloride andpolypropylene resins; fiber-forming semisynthetic polymers, for example,cellulose acetates and regenerated polymers, for example, regeneratedcelluloses, etc. In consideration of the ease or the difficulty in theproduction of the flat multifilament yarns, fiber-forming thermoplasticpolymers capable of being formed into fibers by a melt-spinning method,for example, polyesters, for example, polyethylene terephthalate,trimethylene terephthalate, etc.; polyamides, for example, nylon 6,nylon 66, etc., polyvinylidene chloride and polypropylene, arepreferably used.

In the fiber-forming artificial polymer, an additive comprising at leastone member selected from, for example, delustering agents (for example,titanium dioxide, etc.), fine pore-forming agents (for example, organicsulfonate metal salts, etc.), cationic dye-dyeability-imparting agent(for example, a sulfonium isophthalate salt, etc.), antioxidants (forexample, hindered phenol compounds, etc.), thermostabilizers,flame-retardants (for example, diantimoney trioxide, etc.), fluorescentbrightening agents, coloring materials, antistatic agents, (for example,organic sulfonate metal salt, etc.), moisture-conditioning agents (forexample, polyoxyalkyleneglycols, etc.), and anti-bacterial agents fineparticles, etc.), may be mixed.

There is no limitation to the total thickness of the multifilament yarnand to the thickness of the flat individual filaments usable for thewoven fabric of the present invention, as long as the target wovenfabric of the present invention can be obtained. Usually, the totalthickness of the yarn is preferably 30 to 170 dtex, more preferably 50to 100 dtex and the thickness of the individual filaments is preferably0.5 to 5 dtex, more preferably 1 to 4 dtex.

Also, there is no limitation to the number of twists of the flatmultifilament yarn usable for the flat multifilament yarn woven fabricof the present invention, as long as the target woven fabric of thepresent invention can be obtained.

Namely, the number of twists may be appropriately established inresponse to the use and the necessary properties of the target wovenfabric. Usually, the number of twist is preferably 0 to 2500 turns/m,more preferably 0 to 600 turns/m.

The multifilament yarns usable for the woven fabric of the presentinvention may be textured yarns by false-twisting method, TASLAN methodor air texturing method, for example, an air-interlacing method, as longas the target woven fabric of the present invention can be obtained.

In the woven fabric of the present invention, the warp and/or weft yarnsfrom which the woven fabric is constituted must be constituted from themultifilament yarns comprising a plurality of individual filamentshaving the flat cross-sectional profile as mentioned above.

Namely, the flat multifilament yarns may be used as both the warp andweft yarns, or as either one of the warp and weft yarns, and the othereither one of the warp and weft yarns may be constituted by yarnsdifferent from the flat multifilament yarns.

The different yarns may be selected from monofilament yarns,multifilament yarns and spun yarns. These different yarns may have aspecific property, for example, an anti-static property, a sheeningproperty etc. Also, in the warp and/or weft yarns usable for the wovenfabric of the present invention, a small amount of filaments or fibersdifferent from the flat individual filaments may be used together withthe flat multifilament yarns, as long as the target woven fabric of thepresent invention can be obtained.

In the flat multifilament yarn woven fabric of the present invention,the content of the flat multifilament yarns is preferably 10 to 100% bymass, more preferably 20 to 100% by mass, still more preferably 40 to100% by mass, based on the total mass of the woven fabric.

The flat multifilament yarns for the woven fabric of the presentinvention can be produced by using a spinneret for flat filaments, forexample, a spinneret provided with a plurality of spinning orificeshaving a cross-sectional profile as shown in FIG. 2-C appearing on page5 of Japanese Unexamined Patent Publication No. 56-107,044.

The flat multifilament yarn woven fabric of the present invention can beproduced a conventional weaving procedure in which the flatmultifilament yarns produced as mentioned above are used as warp and/orweft yarns, and can be dyed and finished by a conventional dyeing andfinishing procedures. In the case where the flat multifilament yarns areflat polyester multifilament yarns, the resultant woven fabric may besubjected to a mass-reduction treatment with an alkali. Also, in thefinishing procedures, the woven fabric may be subjected to one or moreof water absorption-enhancing treatments (by coating or impregnatingwith a water-absorbing agent, for example, an anionic hydrophilicpolymeric compound), water-repellent treatments (by coating orimpregnating with a water-repellent agent, for example, awater-repellent fluorine compound), ultraviolet ray-blocking treatments(by applying a dispersion of ultrafine particles of a metal oxide),antistatic treatments, deodorant-applying treatments, mothproofingagent-applying treatments and a light storage agent-applying treatments,successively or simultaneously.

In an embodiment of the flat multifilament yarn woven fabric of thepresent invention, the thickness of the warp and weft yarns and theweave density of the warp and weft yarns are controlled to an extentthat the resultant woven fabric exhibits a cover factor (CF) in therange of from 1500 to 3500.

In the embodiment (1) of the present invention, the cover factor of thewoven fabric is preferably 1500 to 3000 and preferably 1500 to 2500.

Also, in the embodiment (1) of the present invention, the flatmultifilament yarn preferably has a number of twists of 0 to 2500turns/m, more preferably 0 to 600 turns/m, still more preferably 0turn/m, namely non-twisted.

In the embodiment (1) of the present invention, the flat multifilamentyarn woven fabric preferably has an air permeability of 5 ml/cm²·sec orless, more preferably 4 ml/cm²·sec or less, still more preferably 0.1 to3 ml/cm²·sec. The air permeability is determined in accordance with JISL 1096-₁₉₉₈, 6.27.1, Method A (using a Frazir type tester).

In the embodiment (1) of the present invention, the flat multifilamentyarn woven fabric preferably has a water absorption velocity of 40 mm ormore, more preferably 50 to 70 mm, determined in accordance with JIS L1096-₁₉₉₈, 6.26.1 (2) Method (B) (Byreck method) and an abrasionresistance of 50 abrasions or more, more preferably 80 abrasions ormore, still more preferably 100 abrasions or more.

On the embodiment (1) of the present invention, if the cover factor (CF)of the woven fabric is less than 1500, the areas of gaps formed betweenthe warp yearns and the weft yarns may be too large, the resultant wovenfabric may exhibit too high an air permeability (of, for example, morethan 5 ml/cm²·sec) and insufficient water and perspiration-absorbingproperty and an insufficient abrasion resistance. Also, if the coverfactor (CF) of the woven fabric is more than 3500, the warp and weftyarns in the resultant woven fabric may closely contact with each other,the resultant woven fabric may have an insufficient softness and toohigh a flexing resistance and thus the hand of the woven fabric maybecome unsatisfactory and the abrasion resistance of the woven fabricmay be insufficient.

In the flat multifilament yarn woven fabric of the embodiment (1) of thepresent invention having a cover factor of 1500 to 3500, the flatmultifilament yarns from which the warp and/or weft yarns of the wovenfabric are constituted, are flattened and laterally spread due to thecompressive pressure generated at the warp-weft intersecting portions ofthe fabric, under which compressive pressure, the flat individualfilaments contacting each other, at the flat periphery thereof, sliplaterally on each other to make the yarn flat. In this flattening of theyarn, the areas of the gaps between the warp and weft yarns decrease andthus-the resultant woven fabric exhibits a decreased air permeability.Therefore, the flat multifilament yarn woven fabric of the embodiment(1) of the present invention preferably exhibits a low air permeabilityof 5 ml/cm²·sec or less.

In the embodiment (1) of the present invention the flattening of theflat multifilament yarn causes the resultant woven fabric to exhibit adecreased flexing resistance an increased softness and a good soft hand.Also, in the woven fabric of the embodiment (1) of the presentinvention, each of the flat individual filaments in the multifilamentyarns has 3 or more projections extending along the longitudinaldirection of the periphery and 2 or more constrictions formed betweenthe projections, per one side section of the flat profile, and thus theperiphery of the flat individual filament is roughened. Thus, when theindividual filaments in the yarns are brought into contact with eachother, particularly under a compressive pressure generated at theintersecting portions of the warp and weft yarns, the contact area ofthe individual filaments brought into contact with each other isrelatively small, and thus the frictional resistance between theindividual filaments is small. Therefore, the roughened peripheries ofthe individual filaments contributes to enhancing the softness of theresultant woven fabric. Further, in the periphery of each individualfilament, the constrictions extending along the longitudinal directionof the periphery are not, or are substantially not, closed even when theperipheries of the individual filaments are brought into contact witheach other. Therefore, water or perspiration can easily diffuse alongthe constrictions due to the capillary phenomenon, and thus theresultant woven fabric exhibits excellent water andperspiration-absorbing property.

The flat multifilament yarn woven fabric of the embodiment (1) of thepresent invention exhibits an excellent soft hand, a high water andperspiration-absorbing property and a high abrasion resistance and thusis useful as low air permeability textile materials for various clothes,for example, sport clothes and uniform clothes for men and women, andfolk costumes (native dresses), for example, tabes, undergarments,lining clothes, hats caps and fabrics for umbrellas and parasols.

In an embodiment (2) of the flat multi-filament yarn woven fabric of thepresent invention, the multifilament yarns contain a delustering agentin a content of 0.2% by mass or more, preferably 0.4 to 3.5% by mass,more preferably 1.0 to 2.5% by mass, and the woven fabric has a coverfactor (CF) of 1300 to 3000, preferably 1400 to 2500.

There is no limitation to the composition and type of the delusteringagent contained in the multifilament yarn of the flat multifilament yarnwoven fabric of the embodiment (2) of the present invention, as long asthe target woven fabric of the present invention can be obtained.Usually, the delustering agent may comprise at least one type of fineinorganic particles, for example, titanium dioxide and barium sulfate.If the content of the delustering agent is less than 0.2% by mass, onthe basis of the total mass of the multifilaments, the resultantmultifilament yarn may exhibit an insufficient reflectance and thus theresultant woven fabric may be not able to exhibit a satisfactory visionthrough-preventing property. It should be noted that if the content ofthe delustering agent exceeds 7% by mass, the fiber-forming property ofthe resultant polymer composition may become unstable.

If the cover factor (CF) of the woven fabric of the embodiment (2) ofthe present invention is less than 1300, the gaps between the warp andweft yarns may be too large, and the resultant woven fabric may exhibitan unsatisfactory vision through-preventing property. Also, if the coverfactor (CF) if more than 3000, the resultant woven fabric may exhibit aninsufficient softness and an unsatisfactory hand.

In the case where the woven fabric of the embodiment (2) of the presentinvention has a plain weave structure, the cover factor of the plainweave fabric preferably in the range of from 1400 to 1800, morepreferably from 1500 to 1700.

In the case where the woven fabric of the embodiment (2) of the presentinvention has a twill weave structure, the resultant twill weave fabricpreferably has a cover factor (CF) of 1900 to 2400, more preferably 2000to 2300.

There is no specific limitation to the number of twists of themultifilament yarns usable for the woven fabric of the embodiment (2) ofthe present invention, as long as the target woven fabric of the presentinvention can be obtained. However, in order to fully ensure the freedomof movement of the individual filaments in the yarn, relative to eachother, the number of twists of the flat multifilament yarn is preferably0 to 1500 turns/m, more preferably 0 to 600 turns/m. Still morepreferably, the number of twists is 0 turn/m, namely, non-twisted.

In the embodiment (2) of the present invention, the flat multifilamentyarn woven fabric preferably has a degree of vision through-prevention,represented, in a L*a*b* color system, by a differenceΔL(=L*_(w)−L*_(b)) between an L* value of the woven fabric placed on awhite plate, represented by L*_(w), and an L* value of the woven fabricplaced on a black plate, represented by L*_(b), is 15 or less, morepreferably 10 to 13. If the degree ΔL of the vision through preventionis more than 15, the vision through preventing property of the resultantwoven fabric may be insufficient, in practice.

The flat multifilament yarn woven fabric of the embodiment (2) of thepresent invention, preferably has a water absorption velocity of 40 mmor more, more preferably 45 mm or more, still more preferably 50 to 70mm, determined in accordance with JIS L 1096-₁₉₉₈, 6.26.1, (2) Method B(Byreck method). If the water absorption velocity is less than 40 mm,the resultant woven fabric may exhibit insufficient water andperspiration-absorbing property in practice.

In the flat multifilament yarn woven fabric of the embodiment (2) of thepresent invention, the cross-sectional profile of individual filamentsfrom which the flat multifilament yarn is constituted is flat. In thisflat cross-sectional profile, three or more projections and two or moreconstrictions between the projections per one side section of the flatprofile are formed. Thus the peripheries of the individual filamentsbrought into contact with each other exhibit a low frictional resistanceto each other and can easily slip on each other. When a compressivepressure is applied to the multifilament yarns, the individual filamentscan easily move relative to each other along the contacting peripheries,so that the multifilament yarn is flattened and laterally spread. Also,the individual filaments closely contact at the flat peripheries witheach other, to cause the gaps between the yarns arranged in the wovenfabric to be reduced, and the quantity of light transmitted through thewoven fabric to decrease. Also, the delustering agent contained in acontent of 0.2% by mass in the individual filaments causes the lighttransmittance through the resultant woven fabric to reduce and the lightirradiated toward the woven fabric to irregularly reflect on the wovenfabric. Further, the plurality of the projections and constrictionsformed on the peripheries of the individual filaments cause theperipheries of the individual filaments to be roughened to scatter theincident light and to prevent vision through the woven fabric. At theintersecting portions of the warp and weft yarns of the woven fabric,the flattening and spreading of the multifilament yarns can cause theintersecting portions to be softened and the hand of the resultant wovenfabric to be soft.

Further, the constrictions extending along the longitudinal axis of theindividual filament can cause a capillary phenomenon to water andperspiration to be generated and the resultant woven fabric to exhibit ahigh water and perspiration absorption velocity.

Thus, the flat multifilament yarn woven fabric of the embodiment (2) ofthe present invention are useful as a textile material for a use inwhich high vision through-preventing property and water andperspiration-absorbing property are necessary, for example, liningclothes, sport clothes and uniform clothes.

In an embodiment (3) of the flat multifilament yarn woven fabric of thepresent invention, the artificial individual filaments of themultifilament yarn contains a delustering agent in a small content of 0to 0.2% by mass and the woven fabric has a cover factor (CF) in therange of from 800 to 2000.

In the flat multifilament yarn woven fabric of the embodiment (3) of thepresent invention, the content of the delustering agent in theartificial individual filaments are 0 to 0.2% by mass, preferably 0 to0.1% by mass. More preferably, no delustering agent is contained in theindividual filaments. The delustering agent for the present inventionmay be selected from conventional delustering agents, for example,titanium dioxide and barium sulfate. If the content of the delusteringagent is more than 0.2% by mass, in the preferable use of the wovenfabric of the embodiment (3) of the present invention, for example,curtains, the resultant woven fabric may exhibit an insufficient lighttransmittance and thus an unsatisfactory lightening property.

In the flat multifilament yarn woven fabric of the embodiment (3) of thepresent invention, the multifilament yarn preferably has a number oftwists of 0 to 1000 turns/m, more preferably 0 to 200 turns/m, stillmore preferably no twist.

The cover factor (CF) of the flat multifilament yarn woven fabric of theembodiment (3) of the present invention is in the range of from 800 to2000, preferably from 900 to 1800, more preferably from 1000 to 1800.

If the cover factor (CF) is less than 800, in the preferable use of theflat multifilament yarn woven fabric of the embodiment (3) of thepresent invention, for example, curtains, the gaps between the warp andweft yarns in the woven fabric may be too large, and the resultant wovenfabric may exhibit an insufficient vision through-preventing property.Also, if the cover factor is more than 2000, the resultant woven fabricmay exhibit an insufficient lighting property.

The flat multifilament yarn woven fabric of the embodiment (3) of thepresent invention, preferably exhibits a degree of light transmittanceof 10 to 70%, more preferably 20 to 50%, determined in accordance withJIS L 1055-₁₉₈₇, 6.1. Method A, at a degree of illumination of 100000lx. The light transmittance in % is calculated by subtracting alight-blocking rate in % of the woven fabric from 100%. If the lighttransmittance is less than 10%, in the preferable use of the wovenfabric, for example, curtains, the lighting property of the resultantwoven fabric may be insufficient. Also, if the light transmittance ismore than 70%, the resultant woven fabric may exhibit an insufficientvision through-preventing property.

The flat multifilament yarn woven fabric of the embodiment (3) of thepresent invention preferably is non-colored or dyed into a light ormoderate color. The type and amount of the dye used for dyeing may beestablished in view of the use and necessary properties of the resultantdyed woven fabric.

In the flat multifilament yarn woven fabric of the embodiment (3) of thepresent invention, the flat multifilaments are laterally spread andflattened at the warp-weft-intersecting portions of the woven fabric dueto a compressive pressure generated in the intersecting portions, theindividual filaments are, at flat peripheries thereof, closely contactedwith each other, to form a dense structure. In this dense structure, thegaps between the warp and weft yarns are small, and the quantity of thelight passing through the gaps is reduced. A small amount of the lightpassing through the gaps is diffracted in the small gaps andtransmitting light rays through the small gaps adjacent to each otherinterfere with each other, to enhance the vision through-preventingeffect of the woven fabric. Also, the specific cross-sectional profileof the flat individual filaments in the multifilament yarn causes theirregular reflection of the incident light on the peripheries of theindividual filaments and the refraction of the light transmitted throughthe filaments are increased in comparison with filaments having a flatcross-sectional profile and provided with smooth peripheries, filamentshaving a circular cross-sectional profile, and filaments having atriangular cross-sectional profile. Thus, the resultant woven fabricexhibits an excellent vision through-preventing effect without reducingthe lighting property thereof.

The flat multifilament yarn woven fabric of the embodiment (3) of thepresent invention exhibits good soft hand, a low flexing resistance, alow air permeability and a high abrasion resistance, similar to those ofthe embodiments (1) and (2).

For the reasons as mentioned above, the flat multifilament yarn wovenfabric of the embodiment (3) of the present invention is useful forvision through-preventing textile materials for interior, for example,curtains, roll blinds (shades) and partitions.

EXAMPLES

The present invention will be further illustrated by the followingexamples which are not intended to limit the scope of the presentinvention in any way.

Example 1

A polyethylene terephthalate resin was melt-extruded at a temperature of300° C. through 30 melt-spinning orifices formed in a melt-spinneret andhaving a hole shape corresponding to the cross-sectional profile of afilament shown in FIG. 1, which profile has 4 circular arc-shapedprojections and 3 constrictions formed between the projections, per oneside section of the profile, formed on both the sides of a longitudinalcenter line of the profile. The extruded filamentary melt streams weretaken up at a taking up speed of 4000 m/minute, while cool-solidifyingthe melt streams. The resultant undrawn multifilaments were, withoutwinding up, directly drawn at a temperature of 97° C. at a draw ratio of1.3, to prepare a drawn multifilament yarn having a yarn count of 84dt/30 filaments. The individual filaments of the multifilament yarn hada cross-sectional profile as shown in FIG. 1, a flatness of thecross-sectional profile of 3.2, and a filament width ratio C1/C2 was1.2.

The flat multifilament yarns, which were kept non-twisted, were used aswarp and weft yarns to produce a plain weave having the following warpand weft densities.

-   -   Warp density: 101 warps/2.54 cm    -   Weft density: 90 wefts/2.54 cm

In the resultant plain weave, a content of the flat multifilament yarnwas 100%. The plain weave was finished by scouring and dyeing. Thefinished plain weave had a cover factor (CF) of 1782.

The finished plain weave was subjected to the following tests.

(1) Air Permeability

The air permeability of the woven fabric was determined in accordancewith JIS L 1096-₁₉₉₈, 6.27.1, Method A (using a Frazir type tester).

(2) Abrasion Resistance

The abrasion resistance of the woven fabric was determined in accordancewith JIS L 1096-₁₉₉₈, 6.17.1, (1) Method A-1 (flat surface method).

(3) Water-Absorbing Property

A water-absorption velocity of the woven fabric was determined inaccordance with JIS L 1096-₁₉₉₈, 6.26.1, (2) Method B (Byreck method).

(4) Hand

The hand of the woven fabric was evaluated, by touching with a hand,into the following five classes. Class Hand 5 Very high softness,Excellent good hand 4 High softness, Good hand 3 Sufficient softness,Satisfactory hand 2 Slightly insufficient softness, Slightlyunsatisfactory hand 1 Insufficient softness, Unsatisfactory hand

(5) General Evaluation.

The general evaluation results of the tested woven fabric were shown inthe following four classes. Class General evaluation 4 Excellent 3 Good2 Slightly unsatisfactory 1 Bad

The test results are shown in Table 1.

Example 2

A plain weave of flat multifilament yarns was produced and tested by thesame procedures as in Example 1, with exceptions as shown below. In thecross-sectional profile of the flat individual filaments, the number ofthe circular arc-shaped projections was changed from 4 to 3, and thenumber of the constrictions was changed from 3 to 2, per one side of thelongitudinal center line of the flat profile.

The flatness (B/C1) of the flat cross-sectional profile was 3.2, theratio (C1/C2) was 1.2, and the cover factor of the plain weave was 1782.

The test results are shown in Table 1.

Comparative Example 1

A plain weave of flat multifilament yarns was produced and tested by thesame procedures as in Example 1, with exceptions as shown below.

In the flat cross-sectional profile of the individual filaments, noconstrictions were formed.

The flatness (B/C1) of the flat cross-sectional profile was 3.2, theratio (C1/C2) was 1.0, and the cover factor of the plain weave was 1782.

The test results are shown in Table 1.

Comparative Example 2

A plain weave of multifilament yarns was produced and tested by the sameprocedures as in Example 1, with exceptions as shown below.

The flat cross-sectional profile of the individual filaments was changedto a circular cross-sectional profile.

The cover factor of the resultant plain weave was 1782.

The test results are shown in Table 1. TABLE 1 Item Cross-sectionalprofile Construction Abrasion Water- number Cover Air resistanceabsorption Example (per one Ratio Ratio factor permeability (Abrasionvelocity General No. side) (B/C1) (C1/C2) (CF) (ml/cm² · s) number (mm)Hand evaluation Example 1 3 3.2 1.2 1782 0.74 110 55 5 4 2 2 3.2 1.21782 0.92 82 50 5 4 Comparative 1 0 3.2 1.0 1782 2.75 56 20 4 2 Example2 Circular 1782 5.55 45 22 2 1

Example 3

A polyethylene terephthalate resin containing 2.5% by mass of adelustering agent consisting of titanium dioxide was melt-extruded at atemperature of 300° C. through 30 melt-spinning orifices formed in amelt-spinneret and having a hole shape corresponding to thecross-sectional profile of a filament shown in FIG. 1, which profile has4 circular arc-shaped projections and 3 constrictions formed between theprojections, per one side section of the profile, formed on both thesides of a longitudinal center line of the profile. The extrudedfilamentary melt streams were taken up at a taking up speed of 4000m/minute, while cool-solidifying the melt streams. The resultant undrawnmultifilaments were, without winding up, directly drawn at a temperatureof 97° C. at a draw ratio of 1.3, to prepare a drawn multifilament yarnhaving a yarn count of 84 dt/30 filaments. The individual filaments ofthe multifilament yarn had a cross-sectional profile as shown in FIG. 1,a flatness of the cross-sectional profile of 3.2, and a filament widthratio C1/C2 was 1.2.

The flat multifilament yarns, which were kept non-twisted, were used aswarp and weft yarns to produce a plain weave having the following warpand weft densities.

-   -   Warp density: 101 warps/2.54 cm    -   Weft density: 84 wefts/2.54 cm

In the resultant plain weave, a content of the flat multifilament yarnwas 100%. The plain weave was finished by scouring and dyeing. Thefinished plain weave had a cover factor (CF) of 1700.

The resultant woven fabric was subjected to the following tests.

(1) Degree of Vision Through-Prevention

The degree of vision through prevention of the woven fabric subjected tothe test was represented, in a L*a*b* color system, by a differenceΔL(=L*_(w-)−L*_(b)) between an L* value of the woven fabric placed on awhile plate, represented by L*_(w), and an L* value of the woven fabricplaced on a black plate, represented by L*_(b).

(2) Water-Absorbing Property

The water absorption velocity of the woven fabric was determined inaccordance with JIS L 1096-₁₉₉₈, 6.26.1, (2) Method B (Byreck method),as in Example 1.

(3) Hand

The hand of the woven fabric was evaluated, by touching with a hand,into the following five classes, as in Example 1. Class Hand 5 Very highsoftness, Excellent good hand 4 High softness, Good hand 3 Sufficientsoftness, Satisfactory hand 2 Slightly insufficient softness, Slightlyunsatisfactory hand 1 Insufficient softness, Unsatisfactory hand

(5) General Evaluation.

The general evaluation results of the tested woven fabric were shown inthe following four classes, as in Example 1. Class General evaluation 4Excellent 3 Good 2 Slightly unsatisfactory 1 Bad

The test results are shown in Table 2.

Example 4

A plain weave of flat multifilament yarns was produced and tested by thesame procedures as in Example 3, with exceptions as shown below.

In the cross-sectional profile of the flat individual filaments, thenumber of the circular arc-shaped projections was changed from 4 to 3,and the number of the constrictions was changed from 3 to 2, per oneside of the longitudinal center line of the flat profile.

The flatness (B/C1) of the flat cross-sectional profile was 3.2, theratio (C1/C2) was 1.2, and the cover factor of the plain weave was 1700.

The test results are shown in Table 2.

Comparative Example 3

A plain weave of flat multifilament yarns was produced and tested by thesame procedures as in Example 3, with exceptions as shown below.

In the flat cross-sectional profile of the individual filaments, noconstrictions were formed.

The flatness (B/C1) of the flat cross-sectional profile was 3.2, theratio (C1/C2) was 1.0, and the cover factor of the plain weave was 1700.

The test results are shown in Table 2.

Comparative Example 4

A plain weave of multifilament yarns was produced and tested by the sameprocedures as in Example 3, with exceptions as shown below.

The flat cross-sectional profile of the individual filaments was changedto a circular cross-sectional profile.

The cover factor of the resultant plain weave was 1700.

The test results are shown in Table 2. TABLE 2 Item Cross-sectionalprofile Degree of Constriction vision Water- number Cover through-absorption Example (per one Ratio Ratio factor prevention velocityGeneral No. side) (B/C1) (C1/C2) (CF) (Δ L) (mm) Hand evaluation Example3 3 3.2 1.2 1700 12.5 55 5 4 4 2 3.2 1.2 1700 12.4 50 5 4 Comparative 30 3.2 1.0 1700 13.4 20 4 2 Example 4 Circular 1700 15.0 22 2 1

Example 5

A polyethylene terephthalate resin containing no delustering agent wasmelt-extruded at a temperature of 300° C. through 30 melt-spinningorifices formed in a melt-spinnert and having a hole shape correspondingto the cross-sectional profile of a filament shown in FIG. 1, whichprofile has 4 circular arc-shaped projections and 3 constrictions formedbetween the projections, per one side section of the profile, formed onboth the sides of a longitudinal center line of the profile. Theextruded filamentary melt streams were taken up at a taking up speed of4000 m/minute, while cool-solidifying the melt streams. The resultantundrawn multifilaments were, without winding up, directly drawn at atemperature of 97° C. at a draw ratio of 1.3, to prepare a drawnmultifilament yarn having a yarn count of 84 dt/30 filaments. Theindividual filaments of the multifilament yarn had a cross-sectionalprofile as shown in FIG. 1, a flatness of the cross-sectional profile of3.2, and a filament width ratio C1/C2 was 1.2.

The flat multifilament yarns, which were kept non-twisted, were used aswarp and weft yarns to produce a plain weave having the following warpand weft densities.

-   -   Warp density: 63 warps/2.54 cm    -   Weft density: 52 weft/2.54 cm

In the resultant plain weave, a content of the flat multifilament yarnwas 100%. The plain weave was finished by scouring and dyeing. Thefinished plain weave had a cover factor (CF) of 1000.

The resultant woven fabric was subjected to the following tests.

(1) Light Transmittance

The woven fabric was subjected to a measurement of a light blocking ratein accordance with JIS L 1055-₁₉₈₇, 6.1, Method A at a degree ofillumination of 100,000 lx, and the light transmittance through thewoven fabric was calculated in accordance with the following equation.Light transmittance (%)=100−Light blocking rate (%)

(2) Vision Through-Preventing Property

Vision Through-Preventing Property in the Daytime

In a room lighted at an illumination of 700 lx by using a 80Wfluorescent lamp for a room, an article (color: red, form: rectangularparallelepiped, dimensions: 15 cm×7 cm×7 cm) to be seen through a wovenfabric was placed at a location of 20 cm far from a surface of the wovenfabric, and the naked eye of an observer was positioned outside of theroom at a location of 30 cm away from the opposite surface of the wovenfabric and at an illumination of 100,000 lx of sunlight, to allow theobserver to see the article through the woven fabric.

The degree of the vision through-prevention of the woven fabric in thedaytime was evaluated in the following four classes. Class Degree ofvision through prevention 4 Completely not able to recognize the article3 Slightly able to recognize the article 2 Approximately able torecognize the contours of the article 1 Clearly able to recognize thearticle

Vision Through-Preventing Property in the Nighttime

The vision through-presenting property of the woven fabric in thenighttime was tested by the same method as that for the daytime, exceptthat the observer for the article was positioned outside the room in thenighttime at an illumination of 0.2 lx.

The degree of the vision through-prevention of the woven fabric in thenighttime was evaluated in the same four classes as those in thedaytime.

The test results are shown in Table 3.

Example 6

A plain weave of flat multifilament yarns was produced and tested by thesame procedures as in Example 5, with excerptions as shown below.

The weave structure of the plain weave was changed to that having a warpdensity of 55 warps/2.54 cm and a weft density of 36 wefts/2.54 cm, andthe cover factor (CF) of the resultant plain weave was 880.

The test results are shown in Table 3.

Example 7

A plain weave of flat multifilament yarns was produced and tested by thesame procedures as in Example 5, with exceptions as shown below.

The weave structure of the plain weave was changed to that having a warpdensity of 112 warps/2.54 cm and a weft density of 74 wefts/2.54 cm, andthe cover factor (CF) of the resultant plain weave was 1800.

The test results are shown in Table 3.

Example 8

A plain weave of flat multifilament yarns was produced by the sameprocedures as in Example 5, with exceptions as shown below.

The flat multifilament yarn was twisted at a number of twists of 200turns/m, and the resultant plain weave exhibited a cover factor (CF) of1000.

The test results are shown in Table 3.

Comparative Example 5

A plain weave of flat multifilament yarns was produced and tested by thesame procedures as in Example 5, with exceptions as shown below.

The flat cross-sectional profile of the individual filaments of themultifilament yarn had no constrictions. (Flatness of the flat profile:3.2, Ratio (C1/C2): 1.0).

The resultant woven fabric had a cover factor (CF) of 1000.

The test results are shown in Table 3.

Comparative Example 6

A plain weave of flat multifilament yarns was produced by the sameprocedures as in Example 5, with exceptions as shown below.

The flat cross-sectional profile of the individual filaments of themultifilament yarn was changed to a triangular cross-sectional profile.

The resultant woven fabric had a cover factor of 1000.

The test results are shown in Table 3.

Comparative Example 7

A plain weave of flat multifilament yarns was produced by the sameprocedures as in Example 5, with exceptions as shown below.

The flat cross-sectional profile of the individual filaments of themultifilament yarn was changed to a circular cross-sectional profile.

The resultant woven fabric had a cover factor of 1000.

The test results are shown in Table 3.

Comparative Example 8

A plain weave of flat multifilament yarns was produced by the sameprocedures as in Example 6, with exceptions as shown below.

The flat cross-sectional profile of the individual filaments of themultifilament yarn was changed a triangular cross-sectional profile.

The resultant woven fabric had a cover factor of 880.

The test results are shown in Table 3.

Comparative Example 9

A plain weave of flat multifilament yarns was produced by the sameprocedures as in Example 7, with exceptions as shown below.

The flat cross-sectional profile of the individual filaments of themultifilament yarn was changed to a triangular cross-sectional profile.

The resultant woven fabric had a cover factor of 1800.

The test results are shown in Table 3. TABLE 3 Item Cross-sectionalprofile Number of Vision through- constrictions Cover Light preventingper Ratio Ratio factor transmittance property Example No. one side B/C1C1/C2 (CF) (%) Daytime Nighttime Example 5 3 3.2 1.2 1000 35 4 3 6 3 3.21.2 880 40 3 3 7 3 3.2 1.2 1800 25 4 4 8 3 3.2 1.2 1000 38 3 3Comparative 5 0 3.2 1.0 1000 30 2 2 Example 6 Triangular cross section1000 25 2 1 7 Circular cross section 1000 30 2 2 8 Triangular crosssection 880 30 2 1 9 Triangular cross section 1800 15 3 2

INDUSTRIAL APPLICABILITY OF THE INVENTION

In the flat multifilament yarn woven fabric of the present invention,the specific flat cross-sectional profile of the individual filaments inthe multifilament yarn enables the individual filaments to easily slipon each other due to a compressive pressure generated at theintersecting portions of the warp and weft yarns to cause themultifilament yarn to be flattened and laterally spread, and the gapsbetween the yarns to become narrow. Therefore, the air permeability ofthe woven fabric can be appropriately controlled. The resultant wovenfabric of the present invention exhibits a high abrasion resistance andan excellent water and perspiration absorbing property, and can scatterthe incident light by diffraction and irregular reflection of the light,to reduce the vision through property of the woven fabric, withoutsignificantly decreasing the light transmittance of the woven fabric.Accordingly, the flat multifilament yarn woven fabric of the presentinvention is useful as a low air permeability textile material, a visionthrough-preventing textile material, a water and perspiration-absorbingtextile material and lighting, vision through-preventing textilematerial.

1. A flat multifilament yarn woven fabric comprising a plurality ofmultifilament yarns comprising a plurality of artificial individualfilaments comprising, as a principal component, an artificialfiber-forming polymer and having a flat cross-sectional profile, whereinin both the side sections of a longitudinal center line of the flatcross sectional profile of each artificial individual filament, at leastthree projections per side section are projecting outward from thelongitudinal center line and at least two constrictions per side sectionformed between the projections are formed approximately in symmetry withrespect to the longitudinal center line, and a degree of flatness of thecross-sectional profile represented by a ratio (B/C1) of a largestlength (B) of the cross-sectional profile in the direction of thelongitudinal center line to a largest width (C1) of the cross-sectionalprofile in the direction at right angles to the longitudinal center lineis 2 to 6, and woven fabric has a cover factor of 800 to
 3500. 2. Theflat multifilament yarn woven fabric as claimed in claim 1, wherein theartificial fiber-forming polymer is selected from polyesters,polyamides, polyvinylidene chloride, polypropylene, regeneratedcellulose and cellulose acetates.
 3. The flat multifilament yarn wovenfabric as claimed in claim 1, wherein in the cross-sectional profile ofthe artificial individual filaments, a ratio (C1/C2) of the largestwidth (C1) to a smallest width (C2) is in the range of from 1.05 to4.00.
 4. The flat multifilament yarn woven fabric as claimed in claim 1,wherein the total thickness of the multifilament yarns is in the rangeof from 30 to 170 dtex and the thickness of the individual filaments isin the range of from 0.5 to 5 dtex.
 5. The flat multifilament yarn wovenfabric as claimed in claim 1, having a weave structure selected fromplain weave, twill weave and satin weave structures.
 6. The flatmultifilament yarn woven fabric as claimed in claim 1, wherein themultifilament yarns comprising the artificial individual filamentshaving the flat cross-sectional profile is contained in an amount of 10to 100% by mass based on the mass of the fabric.
 7. The flatmultifilament yarn woven fabric as claimed in claim 1, wherein the coverfactor of the woven fabric is in the range of from 1500 to
 3500. 8. Theflat multifilament yarn woven fabric as claimed in claim 7, wherein themultifilament yarn has a number of twists of 0 to 2500 turns/m.
 9. Theflat multifilament yarn woven fabric as claimed in claim 7, having anair permeability of 5 ml/cm²·sec or less, determined in accordance withJIS L 1096-₁₉₉₈, 6.27.1, Method A (using a Frazir type tester).
 10. Theflat multifilament yarn woven fabric as claimed in claim 9, wherein theair-permeability is in the range of from 0.1 to 4.0 ml/cm²·sec.
 11. Theflat multifilament yarn woven fabric as claimed in claim 7, having awater absorption velocity of 40 mm or more, determined in accordancewith JIS L 1096-₁₉₉₈, 6.26.1, (2) Method B (Byreck method).
 12. The flatmultifilament yarn woven fabric as claimed in claim 7, having anabrasion resistance of 50 or more abrasions, determined in accordancewith JIS L 1096-₁₉₉₈, 6.17.1, (1) Method A-1 (flat surface method). 13.A low air permeability textile material comprising a flat multifilamentyarn woven fabric as claimed in any of claims 7 to
 12. 14. The flatmultifilament yarn woven fabric as claimed in claim 1, wherein theartificial individual filaments of the multifilament yarn contains 0.2%or more by mass of a delustering agent and the cover factor of the wovenfabric is in the range of from 1300 to
 3000. 15. The flat multifilamentyarn woven fabric as claimed in claim 14, wherein the multifilament yarnhas a number of twists of 0 to 1500 turns/m.
 16. The flat multifilamentyarn woven fabric as claimed in claim 14, having a degree of visionthrough-prevention of the woven fabric represented, in a L*a*b* colorsystem, by a difference ΔL(L=L*_(w)−L*_(b)) between an L* value of thewoven fabric placed on a white plate, represented by L*_(w), and an L*value of the woven fabric placed on a black plate, represented byL*_(b), is 15 or less.
 17. The flat multifilament yarn woven fabric asclaimed in claim 14, having a water absorption velocity of 40 mm ormore, determined in accordance with JIS L 1096-₁₉₉₈, 6.26.1, (2) MethodB (Byreck method).
 18. A vision through-preventive,perspiration-absorbent textile material comprising a flat multifilamentyarn woven fabric as claimed in any of claims 14 to
 17. 19. The flatmultifilament yarn woven fabric as claimed in claim 1, wherein theartificial individual filaments of the multifilament yarn contains 0 to0.2% by mass and the cover factor of the woven fabric is in the range offrom 800 to
 2000. 20. The flat multifilament yarn woven fabric asclaimed in claim 19, wherein the multifilament yarn has a number oftwists of 0 to 1000 turns/m.
 21. The flat multifilament yarn wovenfabric as claimed in claim 19, having a degree of light transmittance of10 to 70%, determined in accordance with JIS L 1055-₁₉₈₇, 6.1. Method A,at a degree of illumination of 100000 lx.
 22. A visionthrough-preventive textile material comprising a flat multifilament yarnwoven fabric as claimed in any of claims 19 to 21.